CVE-2026-4395

Critical

Description

Heap-based buffer overflow in the KCAPI ECC code path of wc_ecc_import_x963_ex() in wolfSSL wolfcrypt allows a remote attacker to write attacker-controlled data past the bounds of the pubkey_raw buffer via a crafted oversized EC public key point. The WOLFSSL_KCAPI_ECC code path copies the input to key->pubkey_raw (132 bytes) using XMEMCPY without a bounds check, unlike the ATECC code path which includes a length validation. This can be triggered during TLS key exchange when a malicious peer sends a crafted ECPoint in ServerKeyExchange.

SeverityCritical

CVSS9.8

Exploit probability—

ProductWolfssl

PublishedMar 19, 2026

First seenMar 19, 2026

Weakness typeCWE-122CWE-122

How to fix

Update

wolfssl wolfssl5.9.0 or later

Patches

github.com/wolfSSL/wolfssl/pull/9988

Affected products

Product	Affected versions	Fixed in
wolfssl wolfssl	v < 5.9.0	5.9.0

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